Laser devices utilizing alexandrite laser operating at or near its gain peak as shorter-wavelength pumping sources and methods of use thereof

ABSTRACT

In some embodiments, the instant invention provides for a system that includes at least the following components: (i) an Alexandrite laser pumping subsystem; where the Alexandrite laser pumping subsystem is configured to: 1) produce wavelengths between 700 and 820 nm, and 2) produce a pump pulse having: i) a duration between 1 to 10 milliseconds, and ii) an energy measuring up to 100 Joules; where the Alexandrite laser pumping subsystem includes: 1) an optical fiber, and 2) a Lens system, (ii) a Thulium doped Yttrium Aluminum Garnet (Tm:YAG) laser subsystem; where the Tm:YAG laser subsystem includes: 1) a Tm:YAG gain medium, 2) a rod heat sink, and 3) at least one cooling device, (iii) a wavelength selecting device, where the wavelength selecting device is configured to deliver a wavelength between 1.75 microns to 2.1 microns; and where the system is configured to produce a high energy conversion efficiency.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/216,387, entitled “LASER DEVICES UTILIZING ALEXANDRITE LASEROPERATING AT OR NEAR ITS GAIN PEAK AS SHORTER-WAVELENGTH PUMPING SOURCESAND METHODS OF USE THEREOF,” filed Mar. 17, 2014, which claims thepriority of U.S. provisional application Ser. No. 61/791,340, entitled“LASER DEVICES UTILIZING ALEXANDRITE LASER AS PUMPING SOURCE AND METHODSOF USE THEREOF,” filed Mar. 15, 2013; and U.S. provisional applicationSer. No. 61/883,716, entitled “LASER DEVICES UTILIZING ALEXANDRITE LASEROPERATING AT OR NEAR ITS GAIN PEAK AS SHORTER-WAVELENGTH PUMPING SOURCESAND METHODS OF USE THEREOF,” filed Sep. 27, 2013, which are incorporatedherein by reference in their entireties for all purposes.

FIELD OF THE INVENTION

The embodiments of the present invention relate to laser devicesutilizing Alexandrite laser operating at or near its gain peak asshorter-wavelength pumping sources and methods of use thereof.

BACKGROUND OF INVENTION

In some instances, Alexandrite laser systems, which utilize analexandrite crystal as a gain medium, are typically utilized inDermatology, laser machining, and remote sensing technology. In someinstances, pump sources for the alexandrite crystal in the Alexandritelaser systems can, typically, be selected from the group consisting of,but is not limited to: a flashlamp, a laser diode, a mercury arc, andother similarly suitable source. In some instances, the Alexandritelaser systems are typically tuned to an operation wavelength in therange of, e.g., 700 to 820 nm.

BRIEF SUMMARY OF INVENTION

In some embodiments, the instant invention provides for a system thatincludes at least the following components: (i) an Alexandrite laserpumping subsystem; where the Alexandrite laser pumping subsystem isconfigured to: 1) produce wavelengths between 700 and 820 nm, and 2)produce a pump pulse having: i) a duration between 1 to 10 milliseconds,and ii) an energy measuring up to 100 Joules; where the Alexandritelaser pumping subsystem includes: 1) at least one optical fiber, and 2)at least one Lens system, where the at least one optical fiber isconfigured to deliver an Alexandrite output beam of an Alexandrite gainmedium into the at least one Lens system; (ii) a Thulium doped YttriumAluminum Garnet (Tm:YAG) laser subsystem; where the Tm:YAG lasersubsystem includes: 1) a Tm:YAG gain medium; where a Tm:YAG gain mediumof the Tm:YAG laser subsystem is optically pumped by the Alexandritelaser pumping subsystem; where the Tm:YAG gain medium is doped with Tm3+ions to a concentration of between 1% and 50% Tm3+ ions; and where theat least one Lens system is configured to collimate the Alexandriteoutput beam from the at least one optical fiber to a size that issmaller than a diameter of the Tm:YAG gain medium; 2) a rod heat sink,where the rod heat sink encases the Tm:YAG gain medium; and 3) at leastone cooling device, where the at least one cooling device is configuredto stabilize the temperature of the Tm:YAG gain medium; (iii) awavelength selecting device, where the wavelength selecting device isconfigured to deliver a wavelength between 1.75 microns to 2.1 microns;and where the system is configured to produce a high energy conversionefficiency at: 1) multi-Joule-Level pulse energies and 2) multi-WattLevel average powers.

In some embodiments, the Alexandrite laser pumping subsystem furtherincludes: (i) a fiber input adapter and (ii) at least one input lens,where the at least one input lens is encased in the fiber input adapter.

In some embodiments, the Tm:YAG laser subsystem further includes: (i) arod heat sink, where the rod heat sink is directly contacting the fiberinput adapter; (ii) a high reflector, where the high reflector isencased in the fiber input adapter and is optically contacting with theat least one input lens; (iii) at least one output coupler, where the atleast one output coupler is directly contacting the heat rod sink; (iv)a dichroic glass, where the dichroic glass is optically contacting theat least one output coupler; and (v) at least one output lens, where theat least one output lens is optically contacting the dichroic glass.

In some embodiments, the system further includes a micro-lens array,where the micro-lens array is configured to form a pattern, where thepattern is determined by a pitch and a focal length of the micro-lensarray; and where the micro-lens array is optically contacting the atleast one output lens.

In some embodiments, the system further includes: a compact Thuliumion-based wavelength convertor configured to fit into a handpiece, wherethe handpiece includes: (i) an air input adapter, (ii) a fiber inputadapter, (iii) an air integrator, (iv) an air output/air guide, and (v)a Tm:YAG output.

In some embodiments, the Alexandrite laser pumping subsystem isconfigured to use cold airflow to remove heat from the Tm:YAG lasersubsystem.

In some embodiments, the system is utilized for a dermatologic surgery,where the dermatologic surgery is selected from the group consisting of:fractional resurfacing of facial actinic keratosis, treatment ofnon-facial photo damage, treatment of actinic cheilitis, treatment ofmacular seborrheic keratosis, treatment of melisma cheilitis, andtreatment by removal of facial wrinkles.

In some embodiments, the Alexandrite output beam measuring between750-760 nm and an output energy measuring between 1 ms-10 ms durationsresults in a Tm:YAG output measuring between 1 J-10 J at 2 microns.

In some embodiments, the Alexandrite output beam is configured to bedelivered at a wavelength of 755 nm.

In some embodiments, the micro-lens array is configured to generate aspot size of about 360 microns and a fill factor of about 10%.

In some embodiments, the Tm:YAG gain medium is in a form of a rodmeasuring 5 mm in diameter and 60 mm in length.

In some embodiments, the system further includes: a cavity configured toencase at least one pump mirror, the Tm:YAG gain medium, and the atleast one output coupler.

In some embodiments, the at least one pump mirror is configured toachieve at least 80% reflectivity for 1.85-2.1 um.

In some embodiments, the instant invention provides for a method thatincludes at least the following steps: (i) utilizing an Alexandritelaser pumping subsystem; where the Alexandrite laser pumping subsystemis configured to: 1) produce wavelengths between 700 and 820 nm, and 2)produce a pump pulse having: i) a duration between 1 to 10 milliseconds,and ii) an energy measuring up to 100 Joules; where the Alexandritelaser pumping subsystem includes: 1) at least one optical fiber, and 2)at least one Lens system, where the at least one optical fiber isconfigured to deliver an Alexandrite output beam of an Alexandrite gainmedium into the at least one Lens system; (ii) utilizing a Thulium dopedYttrium Aluminum Garnet (Tm:YAG) laser subsystem; where the Tm:YAG lasersubsystem includes: 1) a Tm:YAG gain medium; where a Tm:YAG gain mediumof the Tm:YAG laser subsystem is optically pumped by the Alexandritelaser pumping subsystem; where the Tm:YAG gain medium is doped with Tm3+ions to a concentration of between 1% and 50% Tm3+ ions; and where theat least one Lens system is configured to collimate the Alexandriteoutput beam from the at least one optical fiber to a size that issmaller than a diameter of the Tm:YAG gain medium; 2) a rod heat sink,where the rod heat sink encases the Tm:YAG gain medium; and 3) at leastone cooling device, where the at least one cooling device is configuredto stabilize the temperature of the Tm:YAG gain medium; (iii) utilizinga wavelength selecting device, where the wavelength selecting device isconfigured to deliver a wavelength between 1.75 microns to 2.1 microns;and where the system is configured to produce a high energy conversionefficiency at: 1) multi-Joule-Level pulse energies and 2) multi-WattLevel average powers.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further explained with reference to theattached drawings, wherein like structures are referred to by likenumerals throughout the several views. The drawings shown are notnecessarily to scale, with emphasis instead generally being placed uponillustrating the principles of the present invention. Further, somefeatures may be exaggerated to show details of particular components.

FIG. 1 illustrates some embodiments of the present invention.

FIG. 2 illustrates some embodiments of the present invention.

FIG. 3 illustrates some embodiments of the present invention.

FIG. 4 illustrates another embodiment of the present invention.

FIG. 5 illustrates yet another embodiment of the present invention.

FIG. 6 illustrates another embodiment of the present invention.

FIG. 7 illustrates some embodiments of the present invention.

FIG. 8 further illustrates some embodiments of the present invention.

FIG. 9 still further illustrates some embodiments of the presentinvention.

FIG. 10 illustrates some embodiments of the present invention.

FIG. 11 also illustrates some embodiments of the present invention.

FIG. 12 illustrates some embodiments of the present invention.

FIG. 13 further illustrates some embodiments of the present invention.

The figures constitute a part of this specification and includeillustrative embodiments of the present invention and illustrate variousobjects and features thereof. Further, the figures are not necessarilyto scale, some features may be exaggerated to show details of particularcomponents. In addition, any measurements, specifications and the likeshown in the figures are intended to be illustrative, and notrestrictive. Therefore, specific structural and functional detailsdisclosed herein are not to be interpreted as limiting, but merely as arepresentative basis for teaching one skilled in the art to variouslyemploy the present invention.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

Among those benefits and improvements that have been disclosed, otherobjects and advantages of this invention will become apparent from thefollowing description taken in conjunction with the accompanyingfigures. Detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely illustrative of the invention that may be embodied in variousforms. In addition, each of the examples given in connection with thevarious embodiments of the invention which are intended to beillustrative, and not restrictive. Any alterations and furthermodifications of the inventive feature illustrated herein, and anyadditional applications of the principles of the invention asillustrated herein, which would normally occur to one skilled in therelevant art and having possession of this disclosure, are to beconsidered within the scope of the invention.

Throughout the specification and claims, the following terms take themeanings explicitly associated herein, unless the context clearlydictates otherwise. The phrases “in one embodiment” and “in someembodiments” as used herein do not necessarily refer to the sameembodiment(s), though it may. Furthermore, the phrases “in anotherembodiment” and “in some other embodiments” as used herein do notnecessarily refer to a different embodiment, although it may. Thus, asdescribed below, various embodiments of the invention may be readilycombined, without departing from the scope or spirit of the invention.

In addition, as used herein, the term “or” is an inclusive “or”operator, and is equivalent to the term “and/or,” unless the contextclearly dictates otherwise. The term “based on” is not exclusive andallows for being based on additional factors not described, unless thecontext clearly dictates otherwise. In addition, throughout thespecification, the meaning of “a,” “an,” and “the” include pluralreferences. The meaning of “in” includes “in” and “on.”

In some embodiments, the instant invention involves the laser devicesutilizing Alexandrite laser pumping subsystems operating at or near itsgain peak as pumping sources at wavelengths shorter than 800 nm. In someembodiments, the instant invention involves the laser devices utilizingthe Alexandrite laser pumping subsystems operating at or near its gainpeak as pumping sources at wavelengths shorter than 780 nm. In someembodiments, the instant invention involves the laser devices utilizingthe Alexandrite laser pumping subsystems operating at or near its gainpeak as pumping sources at wavelengths between, e.g., 700 and 820 nm. Insome embodiments, the instant invention involves the laser devicesutilizing the Alexandrite laser pumping subsystems operating at or nearits gain peak as pumping sources at wavelengths between, e.g., 720 and780 nm. In some embodiments, the instant invention involves the laserdevices utilizing the Alexandrite laser pumping subsystems operating ator near its gain peak as pumping sources at wavelengths between, e.g.,750 and 765 nm. In some embodiments, the instant invention involves thelaser devices utilizing the Alexandrite laser pumping subsystemsoperating at or near its gain peak as pumping sources at suchwavelengths where the alexandrite crystal has maximum gain and where theAlexandrite laser pumping subsystems are under normal (non-tuned)operation.

In some embodiments, the instant invention involves the laser devicesutilizing the Alexandrite laser pumping subsystems to pump a gain mediumof Thulium doped Yttrium Aluminum Garnet (Tm:YAG).

In some embodiments, the instant invention involves the laser devicesutilizing a q-switched Alexandrite pumping laser subsystems havingnanosecond (ns) pulse durations which are less than a long-pulse (normalmode) alexandrite laser. In some embodiments, the pumped gain mediumexhibits a switched peak (Q-Switching) or peaks having few μs or evensub μs output pulse durations. In some embodiments, the pumped gainmedium exhibits a switched peak (Q-Switching) or peaks having outputpulse durations in the order of, e.g., 10-100 ns.

In some embodiments, the instant invention involves the laser devicesutilizing the Alexandrite pumping laser subsystems having the pumpduration between, e.g., 1 to 3 milliseconds. In some embodiments, theinstant invention involves the laser devices utilizing the Alexandritepumping laser subsystems having the pump duration between, e.g., 1 to 5milliseconds. In some embodiments, the instant invention involves thelaser devices utilizing the Alexandrite pumping laser subsystems havingthe pump duration between, e.g., 1 to 10 milliseconds.

In some embodiments, the instant invention involves the laser devicesutilizing an Alexandrite laser-pumped q-switched Tm:YAG laser employinga saturable absorber. In some embodiments, for example, the instantinvention can utilize saturable absorbers like the one identified byKuo, Yen-Kuang, and Yi-An Chang, “Numerical Study of Passive Q Switchingof a Tm:YAG Laser with a Ho:YLF Solid-State Saturable Absorber,” AppliedOptics 42(2003): 1685-1691, whose the specific disclosures related tosaturable absorbers are hereby incorporated herein by reference for suchspecific purposes. Specifically, the characteristics of the laser outputdepends on the initial population in the ground state of the Ho:YLFsaturable absorber, the location of the saturable absorber, the pumpingrate, the reflectivity of the output coupler, and the focal length ofthe focusing lens. With a typical laser configuration, a Q-switchedlaser pulse of >35 mJ in 30 ns can be obtained.

In some embodiments, the instant invention utilizes: (1) the disclosedpump wavelengths at or near, e.g., 750 to 755 nm and (2) the pump pulseenergies up to 100 Joules used,—to achieve corresponding outputenergies, obtained in the μs and ms pulse duration regimes, withoutsubstantial surface and/or bulk damage to the Tm:YAG crystal.

In some embodiments, the instant invention involves the laser devicesutilizing Alexandrite laser to pump a gain medium of co-doped Tmmaterials, such as Tm:Ho:YAG and other related materials including, butare not limited to, Tm containing YALO and ZBLAN hosts.

In some embodiments, the instant invention allows a high (≈20%optical-to-optical) energy conversion efficiency from, e.g., ≈755 nm to≈2 μm at multi-Joule-level pulse energies and multi-Watt Level averagepowers.

In some embodiments, the inventive laser device of the instant inventionare suitable for applications in cosmetic dermatology and/or othermedical applications such as, but not limited to, using a compact Tmion-based wavelength convertor that fits into a handpiece that can adaptinto a medical Alexandrite laser system. In some embodiments, theinventive laser device of the instant invention utilize active coolingusing cold airflow to remove heat from the Tm-ion laser material isgenerally required for continuous and stable high power operation.

Referring to FIG. 1 that illustrates an exemplary schematicrepresentation of some embodiments of the instant invention. FIG. 1illustrates that some embodiments of the instant invention includesolid-state compact laser systems that utilize a gain medium of Thuliumdoped Yttrium Aluminium Garnet (Tm:YAG) in a form of an elongated object(e.g., rod, rectangular-shaped prism, etc.) which is optically pumped bythe Alexandrite laser system(s). In some embodiments, the suitableAlexandrite lasers can include, but are not limited to, the followinglaser systems:

i) LP laser system: Light Age, Inc.'s Epicare-LP™ (Somerset, N.J.), theAlexandrite laser generating the light output at ˜755 nm, with averagepower up to 65 Watts; pulse rate up to 3 Hz; and pulse duration from,e.g., 3 to 300 ms;

ii) LPX: Light Age, Inc.'s Epicare-LPX™, the Alexandrite lasergenerating the light output at ˜755 nm, with average power up to 100Watts; pulse rate up to 3 Hz; pulse duration from, e.g., 3 to 300 ms;

iii) DUO: Light Age, Inc.'s Epicare-DUO™, the Alexandrite generating thelight output at ˜755 nm and Nd:YAG laser at 1064 nm, with average powerup to 150 Watts; pulse rate from, e.g., 1 to 10 Hz, and pulse durationfrom, e.g., 0.5 ms (millisecond) to 300 ms; and

iv) PAL: Light Age, Inc.'s PAL-101™, the tunable Alexandrite laser from,e.g., 720 to 820 nm, typical power is 10 Watts at 10 Hz; and pulseduration from, e.g., 10 ns (nanosecond) to 10 us (microsecond).

In some embodiments, as shown in FIG. 1, the inventive Tm:YAG systemscan be housed in a small enclosure that can perform as an attachment totreatment head of the Alexandrite laser systems such as LP, LPX, or DUOmedical system.

The inventive solid-state Tm:YAG system operates based at least in parton the following principles. In some embodiments, when Tm3+ ions aredoped into solid-state host crystals (most commonly, YAG), the resultingmedium has a strong absorption band around, e.g., 765 to 785 nm, whichfalls into the emission of Alexandrite lasers. In some embodiments, whenpumped by a light of around 785 nm, Tm:YAG laser has a sufficiently highoptical conversion efficiency. In some embodiment, the Alexandrite lasersystems (e.g., LP, LPX and DUO) are typically designed to lase at fixedwavelength, which is around 755 nm. In some embodiments, the inventivedevice of the instant invention can shift the typical output of theAlexandrite laser systems to a wavelength of 785 nm. In someembodiments, the inventive laser devices of the instant invention canpump the Tm:YAG medium at wavelength of 755 nm but with a relativelylower efficiency.

In some embodiments, the inventive laser devices of the instantinvention can at least partially compensate the relatively lowerefficiency of pumping at the wavelength of 755 nm by: i) utilizing aTm:YAG medium that would be longer in length if the Tm:YAG medium thatwould be pumped at wavelength of 785 nm, and/or ii) increasing Tm3+ ionconcentration. In some embodiments, utilizing a relatively elongatedTm:YAG medium results in improved heat distribution evenly throughoutthe entire Tm:YAG medium which results in lowering risk of the thermalfracture in the Tm:YAG medium.

In some embodiments, the inventive laser devices of the instantinvention utilize the Tm:YAG medium is a form of a rod having 5 mmdiameter and being 60 mm long. In some embodiments, the inventive laserdevices of the instant invention utilize the Tm:YAG medium doped with 4%of Tm3+ ions. In some embodiments, the inventive laser devices of theinstant invention utilize the Tm:YAG medium doped with at least 4% ofTm3+ ions. In some embodiments, the inventive laser devices of theinstant invention utilize the Tm:YAG medium doped with 6% of Tm3+ ions.In some embodiments, the inventive laser devices of the instantinvention utilize the Tm:YAG medium doped with at least 6% of Tm3+ ions.In some embodiments, the inventive laser devices of the instantinvention utilize the Tm:YAG medium doped less than 50% of Tm3+ ions. Insome embodiments, the inventive laser devices of the instant inventionutilize the Tm:YAG medium doped with less than 25% of Tm3+ ions. In someembodiments, the inventive laser devices of the instant inventionutilize the Tm:YAG medium doped with less than 15% of Tm3+ ions. In someembodiments, the inventive laser devices of the instant inventionutilize the Tm:YAG medium doped with less than 10% of Tm3+ ions.

In some embodiments, as shown in FIG. 1, the inventive Tm:YAG systemsinclude at least one optical fiber (101) that delivers the output of theAlexandrite laser into at least one Lens system (102) that is designedto collimate the Alexandrite output beam from fiber to the size that isslightly smaller (less than 25% size deviation) than a cross area or asize of the Tm:YAG medium (e.g., the collimated Alexandrite output beamhas a diameter that is slightly less than the Tm:YAG rod diameter of 5mm). In some embodiments, the collimated Alexandrite output beam has asize that is less than 20% size deviation than a cross area or a size ofthe Tm:YAG medium. In some embodiments, the collimated Alexandriteoutput beam has a size that is less than 15% size deviation than a crossarea or a size of the Tm:YAG medium. In some embodiments, the collimatedAlexandrite output beam has a size that is less than 10% size deviationthan a cross area or a size of the Tm:YAG medium. In some embodiments,the collimated Alexandrite output beam has a size that is less than 5%size deviation than a cross area or a size of the Tm:YAG medium. In someembodiments, the collimated Alexandrite output beam has a size that isless than 1% size deviation than a cross area or a size of the Tm:YAGmedium.

In some embodiments, the Lens system includes at least one lens. In someembodiments, the Lens system includes a plurality of lenses (e.g., atleast two, at least three, at least four, etc.). In some embodiments,lenses of the Lens system have spherical shape. In some embodiments, theinventive devices of the instant invention can utilize various number oflenses having various shapes in order to collimate the Alexandrite beamoutput from the fiber to the size that is about slightly less than thecross section of the Tm:YAG medium that the pumping light impinges(e.g., is about 80% of the Tm:YAG rod diameter.)

In some embodiments, the collimated Alexandrite output beam is directedat the Tm:YAG medium along the longitudinal axis of the Tm:YAG medium.In some embodiments, the collimated Alexandrite output beam is directedat the Tm:YAG medium at a certain angle to the longitudinal axis of theTm:YAG medium.

In some embodiments, as shown in FIG. 1, a cavity (103) which houses theTm:YAG medium consists at least of: at least one pump mirror, the Tm:YAGmedium, and at least one output coupler. In some embodiments, pumpmirror(s)' shape (or curvature) are such to obtain a sufficiently stablecavity which means that light (or photons) can be traveling back andforth between pump mirror and output coupler for many times withoutsignificant loss. In some embodiments, the instant invention utilizes atleast one or more of the following characteristics to design the cavity:

i) stability; and

ii) mode matching with pump laser which ensures that the highestpossible energy extraction efficiency.

In some embodiments, the instant invention allows a flexibility inutilizing mirrors of various numbers of mirror having various shapes aslong as the above two criteria are met. In some embodiments, the instantinvention utilizes the Lascad software program (http://www.las-cad.com)to simulate cavity setup.

In some embodiments, in case of the end pumping scheme is used, theinventive devices of the instant invention utilize pump mirrors thathave the mirror reflectivity (e.g., a high reflector isreflecting >99.5% of light at near infrared (e.g., between 1.85 to 2.1um), and only reflecting <1% of visible pump laser (e.g., between 750 nmto 790 nm). Output coupler can have different reflectivity at nearinfrared (e.g., between 1.85 to 2.1 um), and has no requirement onreflectivity at visible pump. In some embodiments, the inventive devicesof the instant invention utilize pump mirrors having at least 80%reflectivity for, e.g., 1.85-2.1 um.

In some embodiments, the pump mirror is eliminated by coating one Tm:YAGrod end with the desired mirror reflectivity (e.g., a high reflector isreflecting >99.5% of light at near infrared (e.g., between 1.85 to 2.1um), and only reflecting <1% of visible pump laser (e.g., between 750 nmto 790 nm). In some embodiments, the output coupler is eliminated bycoating one Tm:YAG rod end with the desired reflectivity at nearinfrared (e.g., between 1.85 to 2.1 um), and no requirement onreflectivity at visible pump. In some embodiments, both pump mirror andoutput coupler are eliminated by one Tm:YAG rod end coated with mirrorreflectivity (e.g., a high reflector is reflecting >99.5% of light atnear infrared (e.g., between 1.85 to 2.1 um), and only reflecting <1% ofvisible pump laser (e.g., between 750 nm to 790 nm) and the other end ofTm:YAG rod coated with the desired reflectivity at near infrared (e.g.,between 1.85 to 2.1 um), and no requirement on reflectivity at visiblepump.

In some embodiments, the inventive devices of the instant inventionutilize output couplers having at least 50% reflectivity for, e.g.,1.85-2.1 um. In some embodiments, the inventive devices of the instantinvention utilize pump mirrors having at least 85% reflectivity for,e.g., 1.85-2.1 um. In some embodiments, the inventive devices of theinstant invention utilize pump mirrors having at least 95% reflectivityfor, e.g., 1.85-2.1 um. In some embodiments, the inventive devices ofthe instant invention utilize pump mirrors having at least 99%reflectivity for, e.g., 1.85-2.1 um.

In some embodiments, as shown in FIG. 1, the Tm:YAG output from thecavity passes through at least one dichroic glass (104) that is utilizedto reject residue at 755 nm, and allow to obtain the desired output ofthe inventive devices. In some embodiments, the desired output of theinventive devices is a beam having a wavelength of 2 micron.

FIG. 2 shows the measured 2 micron output energy of the Tm:YAG laser insome embodiments of the instant invention as a function of the measuredpumping energy of the Alexandrite laser with different wavelength around755 nm. In same embodiments, the following operation conditions of theAlexandrite laser resulted in the following output energy of Tm:YAG:

i) Alexandrite laser output of 750 nm output at 3 ms durations resultedin the Tm:YAG output of up to 3 J at 2 um;

ii) Alexandrite laser output of 755 nm output at 3 ms durations resultedin the Tm:YAG output of up to 5 J at 2 um;

iii) Alexandrite laser output of 758 nm output at 3 ms durationsresulted in the Tm:YAG output of up to 10 J at 2 um; and

iv) Alexandrite laser output of, e.g., 750-760 nm output at 10 ms orlonger durations resulted in the Tm:YAG output of less than 1 J at 2 um.

In some embodiments, the small wavelength adjustment of the Alexandritelaser output was obtained by utilizing different output coupler(s) inthe LPX Alexandrite laser system, without mechanically or electricallymodification to the LPX Alexandrite laser system. In FIG. 2, all otherparameters, such as Tm:YAG concentration, rod dimension, and the outputcoupler's reflectivity, were the same.

As FIG. 2 illustrates, the output energy of the Tm:YAG laser systems ofthe instant invention is sufficiently high because the Alexandriteoutput is sufficiently closer to the peak absorption of Tm:YAG material.In same embodiments, the output energy of the Tm:YAG laser systems ofthe instant invention is sufficiently high because the Alexandriteoutput has the pumping pulse duration of 3 ms which matches the lifetimeof Tm:YAG material (10 ms nominally). In same embodiments, the outputenergy of the Tm:YAG laser systems of the instant invention issufficiently high because the Alexandrite output produces more than 40Joules pumping energy.

In some embodiments, the gain of Tm:YAG material depends on temperature,and generally decreases as the temperature of Tm:YAG material increasesdue to an increase in up conversion rate. In some embodiments, when theTm:YAG material is pumped by Alexandrite laser, an estimated amount of25% of energy absorbed by the Tm:YAG material is transferred into heat,which in turn will raise the temperature of the Tm:YAG material. In someembodiments, at a pumping rate of 40 W, the heat produced is about 10 W,and is distributed through the whole length of the Tm:YAG material. Insome embodiments, at least one thermal-electric cooler (TEC) can be usedto remove the heat and stabilize the temperature of the Tm:YAG material.In some embodiments, instead of using TEC, the inventive laser systemsof the instant invention can utilize designs (e.g., designs withchillers) that supply airflows from cold air chillers to cool the Tm:YAGmaterial.

In some embodiments, the inventive laser systems of the instantinvention can be utilized in dermatologic surgeries to perform medicaltreatments such as, but not limited to:

i) fractional resurfacing of facial actinic keratoses;

ii) treatment of non-facial photo damage;

iii) treatment of actinic cheilitis;

iv) treatment of macular seborrheic keratoses;

v) treatment of melisma cheilitis; and

vi) remove facial wrinkles.

In some embodiments, the inventive laser systems of the instantinvention can be utilized in light detection and ranging (LIDAR), suchas Coherent Doppler wind detection. In some embodiments, the inventivelaser systems of the instant invention can be utilized in laser radarsystems.

FIG. 3 illustrates principle of laser cavity design in according to someembodiments of the instant invention, which is similar as the one shownin FIG. 1 but differs from FIG. 1 in part that the dichroic mirror (304)is designed to reflect back onto Tm:YAG rod. In some embodiments, thedesign of FIG. 3 can enhance the Tm:YAG laser output by at least 20%. Insome embodiments, the inventive laser device of the instant inventioncan employ an output lens system (305) to expand the beam size of Tm:YAGcavity output, and/or a microlens array system that gives fractionaloutput suitable for, for example but is not limited to, medicalapplications. In FIG. 3, the following numbers represent specific partsof the instant invention: 301 (optical fiber), 302 (input lenses), 303(cavity), 304 (dichroic glass), 305 (output lenses), and 306 (micro-lensarray).

In some embodiments, the inventive laser device of the instant inventioncan employ an air integrator that diverts small part of the cooled airfrom chiller (mainly used for patient comfort in aesthetic procedures)to thermally cool the Tm:YAG rod. In some embodiments, by assembling aTm:YAG cavity into the air integrator, an exemplary Tm:YAG handpiece ofthe instant invention can be integrated into various devices such as,but is not limited to, Light Age aesthetic products, such as EpiCare™LP, LPX and DUO.

FIG. 4 illustrates Tm:YAG handpiece assembly view in accordance withsome exemplary embodiments of the instant invention:

1. air input adapter (401);

2. fiber input adapter (402);

3. air integrator (403);

4. air output/air guide (404); and

5. Tm:YAG output (405).

FIG. 5 illustrates an air integrator sectional view in accordance withsome exemplary embodiments of the instant invention:

1. air channels (501);

2. air exhaust hole (502); and

3. Tm:YAG cavity (503).

FIG. 6 illustrates a Tm:YAG cavity sectional view in accordance withsome exemplary embodiments of the instant invention:

1. fiber input adapter (601);

2. input lenses (602);

3. pump mirror (603);

4. rod heat sink (604);

5. Tm:YAG rod (605);

6. output coupler (606);

7. Dichroic (607);

8. output lenses (608); and

9. micro-lens array (609)

Test Data of an Exemplary Tm:YAG Handpiece in Accordance with SomeExemplary Embodiments of the Instant Invention

Slope Efficiency

FIG. 7 illustrates the slope efficiency of Tm:YAG output at ˜2 micron,with comparison of a handpiece setup (marked as “TRUE handpiece”) and alaboratory setup (marked as “adjustable OC”) in accordance with the someembodiments of the instant invention. The setups were pumped by 756 nmoutput from LightAge's EpiCare™ LPX unit with 3 ms pulse durationsettings. In some embodiments, the latter allows the output coupler tobe adjusted so that the cavity alignment is optimized, while no suchadjustment is in the TRUE handpiece.

Tm:YAG Output without Cooling

FIG. 8 illustrates the output power drop from Tm:YAG handpiece when nocooling is present. FIG. 8 also shows the estimated temperature of rodon the figure. The gray line is a logarithmic fit. The pumping energy isabout 15 J. Thus, in some embodiments, the instant invention utilizescooling in Tm:YAG handpiece design.

Tm:YAG Output (without Microlens Array)

FIG. 9 illustrates a near field image of the Tm:YAGhandpiece output. Inthis specific example, the beam quality (M^2 factor) of the output isabout 30.

Tm:YAG Fractional Output (with Microlens Array)

FIG. 10 illustrates an image of output from Tm:YAGhandpiece equippedwith micro-lens array. In accordance with some embodiments, themicro-lens array in this particular setup of FIG. 10 has, but is notlimited to, 1000 micron pitch with 6.1 cm focal length, and a size of anindividual spot is roughly 400 microns. In some embodiments, a microlensarray for producing fractional output can be utilized for variousdermatology treatments.

In some embodiments, the instant invention can employ various lens array(varied in pitch size and focal length) to form various patterns. Insome embodiments, the instant invention can rely on the pitch and focallength of micro-lens array to determine factors, such as but are notlimited to: the spot size of each fractional spot and the fill factor(the ratio between area covered by illumination and total treatmentarea). In some embodiments, the spot size of each fractional spot andthe fill factor can affect the efficiency and/or efficacy in patienttreatment. For example, in some embodiments, the instant inventionemploy a lens array that results in the spot size around 360 microns andfill factor of 10%.

In some embodiments, for example, the spot size of each fractional spotand the fill factor can be determined as discussed in Polder K D, BruceS., Treatment of melasma using a novel 1,927 nm fractional thulium fiberlaser: A pilot study., Dermatologic Surgery, 2012 (38:199-206), whosethe specific disclosures related to the spot size of fractional spots,the fill factor, the effectiveness and side effects of 1927 nm thuliumdevice on the treatment of melasma are hereby incorporated herein byreference for such specific purposes. Specifically, patients weresubjected to three to four treatment sessions at 4 week intervals, andeach treatment utilized different/distinct spot sizes and fill factors.

Temporal Profile of Tm:YAG Output

FIG. 11 illustrates an exemplary temporal profile of Tm:YAG output. InFIG. 11, the left panel shows output under S-mode, and the right panelshows output under 3-ms mode. For FIG. 11, a semiconductor photodetector(rise time less than 1 ns) was employed to measure the temporal shape ofTm:YAG output, pumped at two different settings by LightAge's EpiCare™LPX. In FIG. 11, the horizontal scale (time) in oscilloscope settings is1 ms/division. FIG. 11 shows that, in some embodiments, the pulseduration is about 0.64 ms when pumped in S-mode, and is about, e.g., 3.5to 4 ms (two-pulse structure) when pumped in 3-ms mode.

Long-Term Stability Test

FIG. 12 illustrates the output stability of Tm:YAG handpiece bycontinuously pumping, at the repetition rate of 1 Hz, the Tm:YAGhandpiece over a period of one hour, with cooling air is on (see FIG. 8for performance without cooling). The output power is logged on a powermeter, and plotted in FIG. 12. In some embodiments, a 15-minute periodoscillation is not critical to the intended operation in accordance withthe principals of the instant invention. In some embodiments, the periodoscillation can be affected by the thermal effect in the pump laserand/or the output from a chiller.

Tm:YAG Handpiece Output Wavelength

FIG. 13 illustrates the measurement of output wavelength in theexemplary setup. For some embodiments, the angle θ between 1st order(deflected beam) and un-deflected beam (0th order) is measured to be35.75 degrees. The wavelength measurement was taken by using commercialgrating, as shown in FIG. 13. The measured wavelength is 1.96 microns,derived from the grating's equation, with 0.04 microns resolution.

In some embodiments, as shown in FIG. 13, the inventive systems of theinstant invention may not include a wavelength limiting/selectingdevice, which can be added depending on a specific application based ondesirability for having wavelength(s) between, e.g., 1.75 um and to 2.1um. In accordance with FIG. 13, the output wavelength then is determinedby the peak gain of Tm:YAG material and the peak location of HR/OCreflectivities. The aperture (1301) and grating at 300 lines/mm (1302)are identified in FIG. 13.

In some embodiments, the instant invention provides for a system thatincludes at least the following components: (i) an Alexandrite laserpumping subsystem; where the Alexandrite laser pumping subsystem isconfigured to: 1) produce wavelengths between 700 and 820 nm, and 2)produce a pump pulse having: i) a duration between 1 to 10 milliseconds,and ii) an energy measuring up to 100 Joules; where the Alexandritelaser pumping subsystem includes: 1) at least one optical fiber, and 2)at least one Lens system, where the at least one optical fiber isconfigured to deliver an Alexandrite output beam of an Alexandrite gainmedium into the at least one Lens system; (ii) a Thulium doped YttriumAluminum Garnet (Tm:YAG) laser subsystem; where the Tm:YAG lasersubsystem includes: 1) a Tm:YAG gain medium; where a Tm:YAG gain mediumof the Tm:YAG laser subsystem is optically pumped by the Alexandritelaser pumping subsystem; where the Tm:YAG gain medium is doped with Tm3+ions to a concentration of between 1% and 50% Tm3+ ions; and where theat least one Lens system is configured to collimate the Alexandriteoutput beam from the at least one optical fiber to a size that issmaller than a diameter of the Tm:YAG gain medium; 2) a rod heat sink,where the rod heat sink encases the Tm:YAG gain medium; and 3) at leastone cooling device, where the at least one cooling device is configuredto stabilize the temperature of the Tm:YAG gain medium; (iii) awavelength selecting device, where the wavelength selecting device isconfigured to deliver a wavelength between 1.75 microns to 2.1 microns;and where the system is configured to produce a high energy conversionefficiency at: 1) multi-Joule-Level pulse energies and 2) multi-WattLevel average powers.

In some embodiments, the Alexandrite laser pumping subsystem furtherincludes: (i) a fiber input adapter and (ii) at least one input lens,where the at least one input lens is encased in the fiber input adapter.

In some embodiments, the Tm:YAG laser subsystem further includes: (i) arod heat sink, where the rod heat sink is directly contacting the fiberinput adapter; (ii) a high reflector, where the high reflector isencased in the fiber input adapter and is optically contacting with theat least one input lens; (iii) at least one output coupler, where the atleast one output coupler is directly contacting the heat rod sink; (iv)a dichroic glass, where the dichroic glass is optically contacting theat least one output coupler; and (v) at least one output lens, where theat least one output lens is optically contacting the dichroic glass.

In some embodiments, the system further includes a micro-lens array,where the micro-lens array is configured to form a pattern, where thepattern is determined by a pitch and a focal length of the micro-lensarray; and where the micro-lens array is optically contacting the atleast one output lens.

In some embodiments, the system further includes: a compact Thuliumion-based wavelength convertor configured to fit into a handpiece, wherethe handpiece includes: (i) an air input adapter, (ii) a fiber inputadapter, (iii) an air integrator, (iv) an air output/air guide, and (v)a Tm:YAG output.

In some embodiments, the Alexandrite laser pumping subsystem isconfigured to use cold airflow to remove heat from the Tm:YAG lasersubsystem.

In some embodiments, the system is utilized for a dermatologic surgery,where the dermatologic surgery is selected from the group consisting of:fractional resurfacing of facial actinic keratosis, treatment ofnon-facial photo damage, treatment of actinic cheilitis, treatment ofmacular seborrheic keratosis, treatment of melisma cheilitis, andtreatment by removal of facial wrinkles.

In some embodiments, the Alexandrite output beam measuring between750-760 nm and an output energy measuring between 1 ms-10 ms durationsresults in a Tm:YAG output measuring between 1 J-10 J at 2 microns.

In some embodiments, the Alexandrite output beam is configured to bedelivered at a wavelength of 755 nm.

In some embodiments, the micro-lens array is configured to generate aspot size of about 360 microns and a fill factor of about 10%.

In some embodiments, the Tm:YAG gain medium is in a form of a rodmeasuring 5 mm in diameter and 60 mm in length.

In some embodiments, the system further includes: a cavity configured toencase at least one pump mirror, the Tm:YAG gain medium, and the atleast one output coupler.

In some embodiments, the at least one pump mirror is configured toachieve at least 80% reflectivity for 1.85-2.1 um.

In some embodiments, the instant invention provides for a method thatincludes at least the following steps: (i) utilizing an Alexandritelaser pumping subsystem; where the Alexandrite laser pumping subsystemis configured to: 1) produce wavelengths between 700 and 820 nm, and 2)produce a pump pulse having: i) a duration between 1 to 10 milliseconds,and ii) an energy measuring up to 100 Joules; where the Alexandritelaser pumping subsystem includes: 1) at least one optical fiber, and 2)at least one Lens system, where the at least one optical fiber isconfigured to deliver an Alexandrite output beam of an Alexandrite gainmedium into the at least one Lens system; (ii) utilizing a Thulium dopedYttrium Aluminum Garnet (Tm:YAG) laser subsystem; where the Tm:YAG lasersubsystem includes: 1) a Tm:YAG gain medium; where a Tm:YAG gain mediumof the Tm:YAG laser subsystem is optically pumped by the Alexandritelaser pumping subsystem; where the Tm:YAG gain medium is doped with Tm3+ions to a concentration of between 1% and 50% Tm3+ ions; and where theat least one Lens system is configured to collimate the Alexandriteoutput beam from the at least one optical fiber to a size that issmaller than a diameter of the Tm:YAG gain medium; 2) a rod heat sink,where the rod heat sink encases the Tm:YAG gain medium; and 3) at leastone cooling device, where the at least one cooling device is configuredto stabilize the temperature of the Tm:YAG gain medium; (iii) utilizinga wavelength selecting device, where the wavelength selecting device isconfigured to deliver a wavelength between 1.75 microns to 2.1 microns;and where the system is configured to produce a high energy conversionefficiency at: 1) multi-Joule-Level pulse energies and 2) multi-WattLevel average powers.

While a number of embodiments of the present invention have beendescribed, it is understood that these embodiments are illustrativeonly, and not restrictive, and that many modifications may becomeapparent to those of ordinary skill in the art. Further, while thedisclosure herein identifies specific applications of the inventivelaser systems, it is understood that those specific application aremerely illustrative and are not limiting. Specifically, as detailedabove, in at least some embodiments, the instant invention is generallydirected to any solid-state laser system in which the Alexandrite laseris utilized as the pumping source.

What is claimed is:
 1. A system comprising: (i) a first laser pumpingsubsystem, wherein the first laser pumping subsystem is alexandrite gainmedium and is configured to: 1) produce a pump pulse having wavelengthsbetween 700 and 820 nm, and 2) said pump pulse having: i) a durationbetween 1 to 100 milliseconds, and ii) an energy measuring between 1 and100 Joules; (ii) a pump pulse delivery subsystem comprising: 1) at leastone optical fiber, and 2) one or more optional pulse conditioningoptics, wherein the at least one optical fiber is configured to deliveran alexandrite pump pulse into the optional conditioning optics whichmay include a focusing element such as a lens for conveyance into asecond pumped laser subsystem incorporating a Thulium (Tm) ioncontaining gain medium, wherein the second pumped laser subsystemconsists of an optical resonator comprising: a Thulium ion containinggain medium such as Tm:YAG or other materials including, but are notlimited to, Tm containing glass, YALO and ZBLAN hosts or co-dopedmaterials such as Tm:Ho:YAG, wherein the optical resonator consists ofmirrors coated to reflect light at the desired lasing wavelength, suchmirrors may be separate from or coated onto a pumped laser gain mediumand wherein such resonator permits the light from the pump pulse toenter the pumped laser gain medium by means of, for example, a dichroicoptic having substantial transmission at the wavelength of the pumppulse and substantial reflection at a pumped laser output wavelength orhaving substantial reflection at wavelength of the pump pulse andsubstantial transmission at the pumped laser output wavelength, or byuse of a dispersive optics to bring the pump pulse into reasonablespatial alignment with the axis of a pumped laser resonator.
 2. TheSystem of claim 1, wherein the gain medium is Tm:YAG and the Tm:YAG gainmedium is doped with Tm3+ ions to a concentration of between 1 and 50atomic percent.
 3. The System of claim 1, wherein the pulse conditioningoptics are configured to collimate the pump pulse from the at least oneoptical fiber to a size that is smaller than a diameter of the Tm:YAGgain medium.
 4. The system of claim 3, wherein the diameter of Tm gainmedium is between 1 mm and 10 mm and the pump pulse impinging on the Tmgain medium is between 0.1 mm and 9 mm.
 5. The laser systems of claim 1,wherein the laser gain medium is in thermal contact with a heat removalsystem, such heat removal system consisting of a static of flowingliquid or a thermally conductive solid material (“heat sink”).
 6. Thelaser system of claim 5, wherein the liquid is water.
 7. The lasersystem of claim 5, wherein the conductive solid material is a metal suchas copper, gold or aluminum or nonmetallic thermally conductive materialsuch as sapphire or undoped YAG.
 8. The laser system of claim 5, whereina cooling device such as a thermo electric cooling element of elements(TECs) or a cold air chiller is used to stabilize the temperature of theheat sink.
 9. The laser system of claim 1, wherein the pumped laserresonator additionally incorporates a wavelength selecting device, andwherein the wavelength selecting device is configured to permit lassingat one or more selected wavelengths between 1.75 microns to 2.1 microns.10. The system of claim 1, wherein the first laser pumping subsystemfurther comprises: (i) a fiber input adapter; and (ii) at least oneinput lens, wherein the at least one input lens is encased in the fiberinput adapter.
 11. The system of claim 1, wherein the Tm:YAG lasersubsystem further comprises: (i) a rod heat sink, wherein the rod heatsink is directly contacting the fiber input adapter; (ii) a highreflector, wherein the high reflector is encased in the fiber inputadapter and is optically contacting with the at least one input lens;(iii) at least one output coupler, wherein the at least one outputcoupler is directly contacting the heat rod sink; (iv) a dichroic glass,wherein the dichroic glass is optically contacting the at least oneoutput coupler; and (v) at least one output lens, wherein the at leastone output lens is optically contacting the dichroic glass.
 12. Thesystem of claim 1, further comprising a micro-lens array, wherein themicro-lens array is configured to form a pattern, wherein the pattern isdetermined by a pitch and a focal length of the micro-lens array, andwherein the micro-lens array is optically contacting the at least oneoutput lens.
 13. The system of claim 1, further comprising: a compactThulium ion-based wavelength convertor configured to fit into ahandpiece, wherein the handpiece comprises: (i) an air input adapter,(ii) a fiber input adapter, (iii) an air integrator, (iv) an airoutput/air guide, and (v) output beam conditioning optics.
 14. Thesystem of claim 1, wherein the first laser pumping subsystem isconfigured to use cold airflow to remove heat from the Tm:YAG lasersubsystem.
 15. The system of claim 1, wherein the system is utilized fora dermatologic surgery, wherein the dermatologic surgery is selectedfrom the group consisting of: fractional resurfacing of facial actinickeratosis, treatment of non-facial photo damage, treatment of actiniccheilitis, treatment of macular seborrheic keratosis, treatment ofmelisma cheilitis, and treatment by removal of facial wrinkles.
 16. Thesystem of claim 1, wherein the Alexandrite output beam measuring between750-760 nm and an output energy measuring between 1 ms-10 ms durationsresults in a Tm:YAG output measuring between 1 J-10 J at 2 microns. 17.The system of claim 16, wherein the Alexandrite output beam isconfigured to be delivered at a wavelength of 755 nm.
 18. The system ofclaim 12, wherein the micro-lens array is configured to generate a spotsize of about 360 microns and a fill factor of about 10%.
 19. The systemof claim 13, further comprising: a cavity configured to encase at leastone pump mirror, the Tm:YAG gain medium, and the at least one outputcoupler.
 20. The system of claim 19, wherein the at least one pumpmirror is configured to achieve at least 80% reflectivity for 1.85-2.1um.